I'm probably repeating myself a lot by now but if the game had better reward structure for evergreen stuff like PvP and Mahjong (and more of such modes, remake chocoboracing and lords of verminion thx) it would carry a lot of people over the patch lull where they have done most things they wanted from the patch.

Player centric stuff that has enough variance from players themselves can create long lasting and enjoyable content.
If they want to take PvE approach, just combine the fancy additional skill and itemization from Eureka/Bozja into Deep Dungeons and add tons of more modifiers and pathways to them, turn it into crazy roguelite where you slowly build overall power but each run can be dramatically different based on your party size and things you find and meet.